1. Field of the Invention
The invention relates to a method of producing a valve arrangement, in particular for an expansion valve, and to a valve arrangement which is provided, for example, in a vehicle air conditioning system operated with refrigerant.
2. Description of Related Art
EP 1 052 463 A1 has disclosed an expansion valve which accommodates a regulating valve in a housing, and this regulating valve opens and closes the expansion valve as a function of an evaporation pressure and a temperature in a second refrigerant passage via an actuating device designed as a thermohead. Flange-mounted as displacement-generating device on the outside of the housing, separately from the regulating valve, is a solenoid valve which activates a valve arranged outside the housing and opens and closes a first passage opening. The valve is supplied by a passage which leads into a feed opening of a valve space. Leading from this valve space is a bypass bore which runs parallel to the valve seat and opens into a further opening, in which the solenoid valve is provided, which opens and closes the bypass opening.
Such bypass bores which are provided parallel to the passage opening of a valve arrangement have the disadvantage that there is the risk of the bypass bore being reduced in diameter or of the bypass bore of small diameter being obstructed by dirt particles.
Furthermore, valve arrangements for an expansion valve have been disclosed in which one or more recesses are made in the valve seat by non-cutting shaping in order to permit a throughflow of refrigerant with a valve arrangement in closed position. These valve seats have the disadvantage that beads are formed by the material deformation or shaping on account of the displacement of the material in the marginal region of the recess, as a result of which the valve-closing member in a closed position does not come fully to bear in the valve seat. In addition, exact production of the recess for forming a basic opening or a bypass is not made possible. Consequently, reproducibility during the production of such valve arrangements to be accurately adjusted is not possible.